Electric synchroscope and synchronizing apparatus



July 14, 1925. 1,546,070

P. F. HARRIS ELECTRIC SYNCHROSCOPE AND SYNCHRONIZING APPARATUS iled April 16, 1925 g O C v D A o G Y E F F/G.

Q G E F l on. K H

Patented July 14, 1 925.

UNITED STATES PATENT OFFICE.

PERGIVAL FRANK HARRIS, OF SOUTH SHIELDS, ENGLAND.

ELECTRIC SYNOHBOSCOPE ,AND SYNCHBONIZIEG APPARATUS.

To all whom it may concern:

Be it known that I, PERCIVAL FRANK HAR- ms, a subject of the King of England, and residing at South Shields, in the county of Durham, En land, have invented certain new and use 111 Im rovements in Electric Svnchroscopes and gynchronizing Apparatus, of which the following is a specification.

This invention relates to electric.synchroscopes and synchronizingv apparatus such as are used for determining the correct moment at which an alternating current generator can be thrown in parallel with one or more other machines.

Many forms of synchroscopes are known and in some cases these act automatically in conjunction with other apparatus to switch the incoming generator into the bus-bar or other circuit. I

The present invention has particular reference to synchroscopes of the rotary type, its object being the provision of simple and eflicient means whereby the incoming machine can be switched in when the synchronizing values of voltage, frequency and phase are suitable.

A rotary synchroscope according to this invention is rovided with two contact members rotating with the spindle, one acting to close the circuit of a time limit closing relay when the frequencies of the machines to be synchronized are within a permissible limit, and the other acting to close a switch circuit controlled by the relay when the phase relationship of the machines is correct.

The synchroscope itself therefore in conjunction with the time limit closing relay takes care of the frequency and phase relationship. Naturally care must be taken that the voltages of the two machines are also in suflicient correspondence. This may be done by providin a gap in what may be termed the phase re ation circuit, such gap being closed by hand when observation shows that the voltages are correct or by a. f

relay or other electromagnetic device acting automatically. In the latter case some form of voltage comparison contact-makmg device is employed, such for instance as two voltmeters each having contact-making pointers or arms moving across a series of conducting strips separated by insulatlng material. It is to be understood, however,

Application filed April 16, 1925. Serial No. 23,694.

that this automatic voltage comparison device is not essential to the present invention.

For the sake of convenience the two contact members rotating with the spindle of the synchroscope will be referred to as the frequency contact member and the phase contact member respectively. Each of these members is conveniently in the form of a segment or strip of metal mounted on a disc or. drum of insulating material fixed on the synchroscope spindle. Each contact member cooperates with two brushes or other contacts in its path of rotation. The frequency contact maker is long as compared with the gap or space between its coo crating contacts and the phase contact mem r is preferably only slightly longer than the gap between its contacts.

The contacts cooperating with the frequency contact'member are in a circuit containing a relay which has a definite time limit setting for closing but an instantaneous opening and resetting action and the arrangement is such that if the frequencies of the two machines are within the permissible limit and the speed of rotation of the spindle consequently low, the comparatively long frequency contact member will keep its cooperating contacts closed for a time sufiicient to allow the relay to close.

The closing of the relay closes a gap in a circuit containing the operating coil of say an oil-switch connecting the incoming machine to the bus-bars, but there is another gap in this switch circuit which is only closed when the phase contact maker is in cooperation with its contacts. Thus if the frequencies are within the permissible limit the switch-operating circuit is set by the acton of the relay but is only completed when the phase relationship between the incoming machine and the bus-bars (i. e. the other machine or machines) is right. 7

The improved synchroscope and synchronizing apparatus is supplied with current rom any suitable source and a sprin -controlled or other switch may be incluifed in the circuit so that machines cannot be thrown in unintentionally.

If desired arrangements may be made to ensure that once the switch circuit has been energized the oil.or other main-switch shall complete its closing'movement.

In the accompanying drawings,

Figure 1 isadia m illustrating one simple arrangement 0 synchronizing apparatus according to this invention, and

Figure 2 is a diagram generally similar to Figure 1 but with some modifications in the circuits" With reference to these figures, A and B are discs of insulating material mounted on or rotating with the spindle of a rotary synchroscope having a pointer C. The details of the synchroscope itself are not shown or described as they may be of any wellknown t' pe. Upon the disc A is a segmental contact member D cooperating with brushes or contacts E and upon the disc B is another segmental contact member F acting in conjunction with brushes or contacts G.

The contact member D (the frequency contact member) is long as compared with the gap or space between its contacts E and the contact member F (the phase contact member) is only slightly longer than the space between its contacts G.

The contacts E. are in a circuit containing the operating coil H of a relay constructed in any wellknown way to have a definite time limit setting for closing but an instantaneous openlng and resetting action. By way of example only the relay is shown as provided with a dash-pot H which can be made in various wellknown ways to func-' tion in the manner referred to. This relay controls a gap J in a circuit containing the operating coil K of a main oil switch K such circuit including also the contacts G, and, in Figure 1, a hand operated switch L.

M and M represent voltmeters connected respectively say to the bus-bars and to the incoming machine. These connections are not shown. Power for operating the synchronizing apparatus is supplied from' any suitable source through conductors N.

The operation of the apparatus is as followsz-If the frequencies of the bus-bars and incoming machine are near enough for synchronizing purposes the speed of rotation of the spindle will be low and the contact member D is sufficiently long to keep the circuit controlled by it and the contacts E closed for a time suflicient to allow the iglay H to close. The gap J will consequently be closed but unless the switch L (Figure 1) is closed and the gap between the contacts G closed by the contact member F glcie operating coil K will not be ener- The switch L is closed when the voltages of the bus-bars and incoming machine correspond sufiici'ently and the gap at G is closed only when the phase relationship is right. When these conditions are satisfied the coil K is energized and the main oil switch K closed thus throwing the machine on to the bus-bars.

. The arrangement shown in Figure 2 is substantially similar to that described with reference to Figure 1 except that the two voltmeters M M are used as contact-making devices controlling through a relay 0 a gap O in the circuit containing the contacts G. Contact arms M M on-the voltmeter spindles move over a series of conducting strips M separated from one another by insulatipn. A hand-operated spring-controlled switch P is provided and when that is closed the action of the synchronizing apparatus becomes automatic as the .circuit containing the main switch K cannot be energized until all the factors of .frequency, phase relationship and voltage are satisfactory.

Obviously the relay or electroma etic circuit-closer 0 might be dispensed w1th if the voltmeter contacts M and M were made capable of carrying the current required to operate the main switch coil K.

What I claim as my invention and desire .tosecure by Letters Patent-is: F

1. In electric synchronizing apparatus the combination with a rotary synchroscope, of two contact members thereon one actin to close the energizing circuit of a time limit closing relay for more than a predetermined time when the frequencies of the machines to be synchronized are within a permissible limit and the other acting to close a switch circuit controlled by the relay when the phase relationship. of the machines is correct.

2. An electric rotary synchroscope having a rotatable spindle, a contact member thereon controlling a circuit containing a time limit closing relay the length of such contact member being such that when the frequency of the two machines is within permissible limits the relay circuit is closed for a time suflicient to allow the relay to operate, the synchroscope spindle being also provided with a second contact member controlling a switch-operating circuit in which circuit is a gap closed by the operation of the relay.

3. In electric synchronizing apparatus, the combination of a synchroscope, a rotary spindle forming part of said synchroscope, two segmental contact members rotating with said spindle, brush or otherrubbing contactscooperating with the first segmental contact member and forming part of an electric circuit including a source of power, a time limit closing relay in said circuit, brush or other rubbing contacts cooperating with the second segmental contact member and forming part of an electric circuit including a source of power, a main switch operating coil in said second circuit and a gap in said second circuit controlled by said time limit closing device.

4. In an electric synchroscope the combination of a rotary spindle, two segmental mental contact member acting to close a contact members rotating with the spindle switch circuit controlled by the relay when 10 each cooperating with two brush or other the phase relationship of the machines is rubbing contacts, one of said segmental concorrect.

I tact members acting to close the circuit of a In testimony whereof I have signed my time limit closing relay when the frequenname to this specification. cies of the machines to be synchronized are a permissible limit and the other seg- PERGIVAL FRANK HARRIS. 

